Nearly 20,000 Egyptian prisoners have gone on a week-long hunger strike inside their jail cells to protest what they allege as inmate mistreatment, an Egyptian rights activist said.

"More than 20,000 prisoners started the hunger strike in more than 114 detention centers and prisons," said Director of Egyptian Center for Human Rights Victims Haytham Abo Khalil, as cited in a Friday report by Anadolu Agency.

He added that the strike is aimed at protesting what he described as the "mistreatment" inside Egyptian prisons.

Abo Khalil said by staging the strike, the prisoners want to draw attention to their sufferings inside the Arab nation’s prisons.

A recent report by the Egyptian Center for Economic and Social Rights (ECESR), a local NGO, documented over 21,000 alleged cases of individuals who had been subject to prosecution since the July 3 ouster of elected president Mohamed Morsi by the military under the leadership of former general and now president-elect Abdel-Fattah al-Sisi.

There have been reports of widespread and systematic mistreatment and torture being carried out in Egyptian detention facilities.